1. Field of the Invention
The present invention relates to the class of duct and pipe joints or couplings. More particularly, the present invention relates to the subclass of particular interfaces originally in sheet form.
2. Description of the Prior Art
Heretofore it has been conventional to employ duct connectors, which used screws, bolts, clips, drives, and other external hardware to connect ducts end-to-end. The prior art connectors also required use of welding and metal working tools of various kinds.
These prior art techniques made installation of rectangular air conditioning ducts slow and laborious. Furthermore, in service, these connectors permitted leakage of conditioned air under pressure from air conditioning systems.
Thus, there exits a need for a duct connector that makes installation of rectangular air conditioning ducts fast and not laborious and which does not permit leakage of conditioned air under pressure from air conditioning systems.
Numerous innovations for duct work connectors have been provided in the prior art. Even though these innovations may be suitable for specific purposes which they address, they each differ in structure operation and/or purpose from the present invention.
FOR EXAMPLE, U.S. Pat. No. 1,935,690 to Zack teaches a joint for metal duct sections comprising a sheet metal body folded to form three folds between two of which one end of a duct section is insertable and between the next two of which the end of the adjoining duct section is inserted. Projections on the two duct sections, and detachable means engaging the projections hold the duct section ends locked between the respective pairs of folds.
ANOTHER EXAMPLE, U.S. Pat. No. 2,275,572 to Somers teaches a sheet metal duct of the type having a plurality of tubular sections and means for connecting the ends of the sections. The means for connecting the ends of the sections comprises a coupling formed of a plurality of bars, each of which has a longitudinally extending groove in each side edge. Cooperative means are provided on the bars for detachably connecting the ends thereof to form an endless collar. Inwardly directed shoulders are formed on the bars within the grooves.
STILL ANOTHER EXAMPLE, U.S. Pat. No. 3,246,918 to Burghart teaches a joint for joining ends of separate air ducts. The joint comprises a first supported air duct having top and bottom walls with end edges, a second air duct having top and bottom walls with unsupported ends, first cleat means joining the end of the second duct top wall to the end of the first duct top wall, and second cleat means joining the end of the second duct bottom wall to the end of the first duct bottom wall. Each of the cleat means is a reversible cleat and comprises a first generally planar sheet-like cleat section having first and second surfaces and first and second edges, a second generally planar sheet-like cleat section having first and second surfaces and first and second edges, the second section being generally parallel to the first section and having its first surface closely facing the second surface of the first section, a third generally planar sheet-like cleat section having first and second edges, the third section being generally parallel to the first and second sections and having a surface closely facing the second surface of the second section, a first integral sheet portion defining an outwardly projecting integral rib along the first edge of the first section generally perpendicular to the first section, a double thickness integral sheet portion comprising an outwardly projecting integral extension of the first section from along the second edge of the first section, the extension being folded over upon itself and extending downwardly to a position below the second edge of the first section and enclosing the second edge of the first section and merging with the second edge of the second section, the extension being generally perpendicular to the first section, the rib and extension being spaced from each other, generally parallel to each other, and defining an inverted channel together with the first clear section, and a joining portion joining the first edge of the second cleat section with the first edge of the third cleat section, the joining portion comprising an integral sheet portion extending in an arc of about 180 degrees to define a fold merging with the first edge of the second and third cleat sections, the first and second and the second and third cleat sections closely face each other to tightly receive the wall ends of opposite ones of the ducts, the first edge of the first section and the first edge of the second section comprising a pair of lips defining a first elongated slit like opening for insertion of the end wall of a duct, the second edge of the second section and a second edge of the third section comprising of pair of lips defining a second elongated slit like opening, the top wall of the first duct having its end portion within the second opening and tightly between the second and third planar sections of the first cleat means, the top wall of the second duct having its end portion overlying the end portion of the first duct top wall and received within the first opening and tightly between the first and second planar sections of the first cleat means, the first duct having its bottom wall end within the first opening and tightly held between the first and second planar sections of the second cleat means and the second duct having its bottom wall end portion overlying and overlapping the first duct bottom wall end portion and received within the second opening and tightly between the second and third planar sections of the second cleat means, and means impaling each of the cleats and the wall ends received thereby and holding the cleat sections with the wall ends tightly sandwiched therebetween.
YET ANOTHER EXAMPLE, U.S. Pat. No. 3,415,543 to Keating teaches a coupling frame including a hollow channel which overlies duct or wall sections to be joined and a pair of reversely folded legs which define opposed wall receiving channels. In the preferred embodiment, the frame is rectangular and defines a chamber which overlies the junction of the duct or wall sections.
STILL YET ANOTHER EXAMPLE, U.S. Pat. No. 4,558,892 to Daw et al. teaches a duct assembly system for joining duct sections, each having a plurality of flat intersecting walls which includes angle member connectors respectively associated with the duct walls. Each connector is generally L-shaped with one leg portion extending perpendicular to the duct wall and having an elongated channel formed therein and the other leg portion comprising two biased-together flanges adapted for frictionally receiving the adjacent duct wall edge therebetween. Each flange has elongated ridges which interlock with elongated ribs on the associated duct wall. Each duct wall edge is embedded in a mastic sealant in a trough in the associated connector. The trough has diverging sides for guiding the duct wall edge thereinto. Connectors on intersecting duct walls are joined by corner members formed of sheet metal and flanged for rigidity and tight fit in the connector channels. Each corner member has flanges for gripping the channel edges of the joined connectors. Adjacent corner members on the two duct sections are joined by fasteners and a gasket may be disposed between the duct sections.
YET STILL ANOTHER EXAMPLE, U.S. Pat. No. 4,941,693 to Spaude et al. teaches a connector for connecting end-to-end two spiral-wound sheet metal air ducts. The connector is an annular structure with opposite end segments, each of which presents an annular recess or groove which is open at its outer end and closed at its inner end and filled with sealing mastic. The dimension of each recess or groove transverse to the longitudinal axis of the ducts and the connector is substantially equal to the maximum thickness of the corresponding duct (i.e., where its spiral rib is located), so that each duct has a snug sliding fit in the corresponding recess.
STILL YET ANOTHER EXAMPLE, U.S. Pat. No. 5,195,789 to Walsh et al. teaches a slip lock connector assembly for joining end-to-end first and second flat-sided ducts made of sheet metal and has a frame like structure defined by a plurality of similar connecting members arranged in coplanar array. Each connecting member is made of pliable sheet metal bent, rolled, and molded to proper form. Each member has a flat main wall with first and second walls at opposite sides defining first and second channels. Both channels are filled with sealant material. The flat end of a side of the first duct in slipped into the first channel and secured by auxiliary fastening elements, whereby the sealant in the first channel seals the connector to the flat end of the first duct. The flat end of a side of the second duct is slipped into the second channel and sealed by the sealant therein. In addition, the wall of the second channel is formed with a rolled ledge which engages with lock projections on a side of the second duct to secure the second duct to the second channel. The second channel may have a laterally extending flange to stiffen the structure of the connecting member.
It has been found that by orienting the folded free edge of the flange toward the ledge, the space above the drill rail that the chuck of the tool that drives the screw into the drill rail must occupy is obstructed and thereby eliminating the clearance needed for the chuck of the tool.
YET STILL ANOTHER EXAMPLE, U.K. Patent Number 1,458,912 to Kelver teaches two ducts having substantially similar quadrangular cross sectional shapes and positioned in an end-to-end relationship. Each duct has an outer wall and a liner overlying the inner surface of the outer wall, the liner of each duct terminating in an end, the outer wall of each duct having an end portion extending beyond the end of its overlying liner, and a clip positioned between the ducts, the clip being elongate and comprising an outer fold extending longitudinally of the clip and joined at one longitudinal edge to one longitudinal edge of the outer fold and bent thereover to form a channel between the outer and middle folds, an inner fold extending longitudinally of the clip and joined at one longitudinal edge to the opposite longitudinal edge of the middle fold and bent thereover to form a channel between the inner and middle folds, a leg extending longitudinally of the clip and projecting substantially perpendicularly from the inner fold between the one longitudinal edge and the opposite longitudinal edge of the inner fold, the leg terminating in a flange spaced overlying the inner fold, the end portion of the outer wall of one duct being positioned in the channel between the outer and middle folds, the end portion of the outer wall of the other duct being positioned in the channel between the inner and middle folds, and the end of the liner of one of the ducts being fitted under the flange and over a portion of the inner fold.
It is apparent that numerous innovations for duct work connectors have been provided in the prior art that are adapted to be used. Furthermore, even though these innovations may be suitable for the specific individual purposes to which they address, however, they would not be suitable for the purposes of the present invention as heretofore described.